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<h1><a name="SECTION0028200000000000000000">
26.2 <tt class="module">__builtin__</tt> --
         Built-in objects</a>
</h1>

<p>
<a name="module-builtin"></a>

<p>
This module provides direct access to all `built-in' identifiers of
Python; for example, <code>__builtin__.open</code> is the full name for the
built-in function <tt class="function">open()</tt>.  See chapter&nbsp;<a href="builtin.html#builtin">2</a>,
``Built-in Objects.''

<p>
This module is not normally accessed explicitly by most applications,
but can be useful in modules that provide objects with the same name
as a built-in value, but in which the built-in of that name is also
needed.  For example, in a module that wants to implement an
<tt class="function">open()</tt> function that wraps the built-in <tt class="function">open()</tt>,
this module can be used directly:

<p>
<div class="verbatim"><pre>
import __builtin__

def open(path):
    f = __builtin__.open(path, 'r')
    return UpperCaser(f)

class UpperCaser:
    '''Wrapper around a file that converts output to upper-case.'''

    def __init__(self, f):
        self._f = f

    def read(self, count=-1):
        return self._f.read(count).upper()

    # ...
</pre></div>

<p>
As an implementation detail, most modules have the name
<code>__builtins__</code> (note the "<tt class="character">s</tt>") made available as part of
their globals.  The value of <code>__builtins__</code> is normally either
this module or the value of this modules's <tt class="member">__dict__</tt>
attribute.  Since this is an implementation detail, it may not be used
by alternate implementations of Python.

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